[Part 3] Added convenience constructors for set of transforms.

src/Microsoft.ML.Transforms/GroupTransform.cs

@@ -88,6 +88,18 @@ public sealed class Arguments : TransformInputBase
 
         private readonly GroupSchema _schema;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="groupKey">Columns to group by</param>
+        /// <param name="columns">Columns to group together</param>
+        public GroupTransform(IHostEnvironment env, IDataView input, string groupKey, params string[] columns)
+            : this(env, new Arguments() { GroupKey = new[] { groupKey }, Column = columns }, input)
+        {
+        }
+
         public GroupTransform(IHostEnvironment env, Arguments args, IDataView input)
             : base(env, RegistrationName, input)
         {

src/Microsoft.ML.Transforms/HashJoinTransform.cs

@@ -37,6 +37,14 @@ public sealed class HashJoinTransform : OneToOneTransformBase
         public const int NumBitsMin = 1;
         public const int NumBitsLim = 32;
 
+        private static class Defaults
+        {
+            public const bool Join = true;
+            public const int HashBits = NumBitsLim - 1;
+            public const uint Seed = 314489979;
+            public const bool Ordered = true;
+        }
+
         public sealed class Arguments : TransformInputBase
         {
             [Argument(ArgumentType.Multiple | ArgumentType.Required, HelpText = "New column definition(s) (optional form: name:src)",
@@ -45,17 +53,17 @@ public sealed class Arguments : TransformInputBase
             public Column[] Column;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "Whether the values need to be combined for a single hash")]
-            public bool Join = true;
+            public bool Join = Defaults.Join;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "Number of bits to hash into. Must be between 1 and 31, inclusive.",
                 ShortName = "bits", SortOrder = 2)]
-            public int HashBits = NumBitsLim - 1;
+            public int HashBits = Defaults.HashBits;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "Hashing seed")]
-            public uint Seed = 314489979;
+            public uint Seed = Defaults.Seed;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "Whether the position of each term should be included in the hash", ShortName = "ord")]
-            public bool Ordered = true;
+            public bool Ordered = Defaults.Ordered;
         }
 
         public sealed class Column : OneToOneColumn
@@ -166,6 +174,25 @@ private static VersionInfo GetVersionInfo()
 
         private readonly ColumnInfoEx[] _exes;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="join">Whether the values need to be combined for a single hash.</param>
+        /// <param name="hashBits">Number of bits to hash into. Must be between 1 and 31, inclusive.</param>
+        public HashJoinTransform(IHostEnvironment env,
+            IDataView input,
+            string name,
+            string source = null,
+             bool join = Defaults.Join,
+            int hashBits = Defaults.HashBits)
+            : this(env, new Arguments() { Column = new[] { new Column() { Source = source ?? name, Name = name } }, Join = join, HashBits = hashBits }, input)
+        {
+        }
+
         public HashJoinTransform(IHostEnvironment env, Arguments args, IDataView input)
             : base(env, RegistrationName, Contracts.CheckRef(args, nameof(args)).Column, input, TestColumnType)
         {

src/Microsoft.ML.Transforms/KeyToBinaryVectorTransform.cs

@@ -54,6 +54,18 @@ private static VersionInfo GetVersionInfo()
 
         private readonly VectorType[] _types;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        public KeyToBinaryVectorTransform(IHostEnvironment env, IDataView input, string name, string source = null)
+            : this(env, new Arguments() { Column = new[] { new KeyToVectorTransform.Column() { Source = source ?? name, Name = name } } }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/LoadTransform.cs

@@ -39,6 +39,25 @@ public class Arguments
 
         internal const string Summary = "Loads specified transforms from the model file and applies them to current data.";
 
+        /// <summary>
+        /// A helper method to create <see cref="LoadTransform"/> for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="modelFile">Model file to load the transforms from.</param>
+        /// <param name="tag">The tags (comma-separated) to be loaded (or omitted, if complement is true).</param>
+        /// <param name="complement">Whether to load all transforms except those marked by tags.</param>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, string modelFile, string[] tag, bool complement = false)
+        {
+            var args = new Arguments()
+            {
+                ModelFile = modelFile,
+                Tag = tag,
+                Complement = complement
+            };
+            return Create(env, args, input);
+        }
+
         public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
         {
             Contracts.CheckValue(env, nameof(env));

src/Microsoft.ML.Transforms/MutualInformationFeatureSelection.cs

@@ -33,6 +33,13 @@ public static class MutualInformationFeatureSelectionTransform
         public const string UserName = "Mutual Information Feature Selection Transform";
         public const string ShortName = "MIFeatureSelection";
 
+        private static class Defaults
+        {
+            public const string LabelColumn = DefaultColumnNames.Label;
+            public const int SlotsInOutput = 1000;
+            public const int NumBins = 256;
+        }
+
         public sealed class Arguments : TransformInputBase
         {
             [Argument(ArgumentType.Multiple | ArgumentType.Required, HelpText = "Columns to use for feature selection", ShortName = "col",
@@ -41,19 +48,45 @@ public sealed class Arguments : TransformInputBase
 
             [Argument(ArgumentType.LastOccurenceWins, HelpText = "Column to use for labels", ShortName = "lab",
                 SortOrder = 4, Purpose = SpecialPurpose.ColumnName)]
-            public string LabelColumn = DefaultColumnNames.Label;
+            public string LabelColumn = Defaults.LabelColumn;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "The maximum number of slots to preserve in output", ShortName = "topk,numSlotsToKeep",
                 SortOrder = 1)]
-            public int SlotsInOutput = 1000;
+            public int SlotsInOutput = Defaults.SlotsInOutput;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "Max number of bins for R4/R8 columns, power of 2 recommended",
                 ShortName = "bins")]
-            public int NumBins = 256;
+            public int NumBins = Defaults.NumBins;
         }
 
         internal static string RegistrationName = "MutualInformationFeatureSelectionTransform";
 
+        /// <summary>
+        /// A helper method to create <see cref="IDataTransform"/> for selecting the top k slots ordered by their mutual information.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="labelColumn">Column to use for labels.</param>
+        /// <param name="slotsInOutput">The maximum number of slots to preserve in output.</param>
+        /// <param name="numBins">Max number of bins for R4/R8 columns, power of 2 recommended.</param>
+        /// <param name="columns">Columns to use for feature selection.</param>
+        public static IDataTransform Create(IHostEnvironment env,
+            IDataView input,
+            string labelColumn = Defaults.LabelColumn,
+            int slotsInOutput = Defaults.SlotsInOutput,
+            int numBins = Defaults.NumBins,
+            params string[] columns)
+        {
+            var args = new Arguments()
+            {
+                Column = columns,
+                LabelColumn = labelColumn,
+                SlotsInOutput = slotsInOutput,
+                NumBins = numBins
+            };
+            return Create(env, args, input);
+        }
+
         /// <summary>
         /// Create method corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/NADropTransform.cs

@@ -69,6 +69,18 @@ private static VersionInfo GetVersionInfo()
         // The isNA delegates, parallel to Infos.
         private readonly Delegate[] _isNAs;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        public NADropTransform(IHostEnvironment env, IDataView input, string name, string source = null)
+            : this(env, new Arguments() { Column = new[] { new Column() { Source = source ?? name, Name = name } } }, input)
+        {
+        }
+
         public NADropTransform(IHostEnvironment env, Arguments args, IDataView input)
             : base(Contracts.CheckRef(env, nameof(env)), RegistrationName, env.CheckRef(args, nameof(args)).Column, input, TestType)
         {

src/Microsoft.ML.Transforms/NAHandleTransform.cs

@@ -36,10 +36,25 @@ public static class NAHandleTransform
     {
         public enum ReplacementKind
         {
+            /// <summary>
+            /// Replace with the default value of the column based on it's type. For example, 'zero' for numeric and 'empty' for string/text columns.
+            /// </summary>
             [EnumValueDisplay("Zero/empty")]
             DefaultValue,
+
+            /// <summary>
+            /// Replace with the mean value of the column. Supports only numeric/time span/ DateTime columns.
+            /// </summary>
             Mean,
+
+            /// <summary>
+            /// Replace with the minimum value of the column. Supports only numeric/time span/ DateTime columns.
+            /// </summary>
             Minimum,
+
+            /// <summary>
+            /// Replace with the maximum value of the column. Supports only numeric/time span/ DateTime columns.
+            /// </summary>
             Maximum,
 
             [HideEnumValue]
@@ -105,6 +120,27 @@ public bool TryUnparse(StringBuilder sb)
         internal const string FriendlyName = "NA Handle Transform";
         internal const string ShortName = "NAHandle";
 
+        /// <summary>
+        /// A helper method to create <see cref="NAHandleTransform"/> for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="replaceWith">The replacement method to utilize.</param>
+        public static IDataTransform Create(IHostEnvironment env, IDataView input, string name, string source = null, ReplacementKind replaceWith = ReplacementKind.DefaultValue)
+        {
+            var args = new Arguments()
+            {
+                Column = new[] 
+                {
+                    new Column() { Source = source ?? name, Name = name }
+                },
+                ReplaceWith = replaceWith
+            };
+            return Create(env, args, input);
+        }
+
         public static IDataTransform Create(IHostEnvironment env, Arguments args, IDataView input)
         {
             Contracts.CheckValue(env, nameof(env));

src/Microsoft.ML.Transforms/NAIndicatorTransform.cs

@@ -85,6 +85,18 @@ private static string TestType(ColumnType type)
         // The output column types, parallel to Infos.
         private readonly ColumnType[] _types;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        public NAIndicatorTransform(IHostEnvironment env, IDataView input, string name, string source = null)
+            : this(env, new Arguments() { Column = new[] { new Column() { Source = source ?? name, Name = name } } }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/NAReplaceTransform.cs

@@ -186,6 +186,19 @@ private static string TestType<T>(ColumnType type)
 
         public override bool CanSaveOnnx => true;
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        /// <param name="replacementKind">The replacement method to utilize.</param>
+        public NAReplaceTransform(IHostEnvironment env, IDataView input, string name, string source = null, ReplacementKind replacementKind = ReplacementKind.DefaultValue)
+            : this(env, new Arguments() { Column = new[] { new Column() { Source = source ?? name, Name = name } }, ReplacementKind = replacementKind }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/OptionalColumnTransform.cs

@@ -26,7 +26,14 @@
 
 namespace Microsoft.ML.Runtime.DataPipe
 {
-    public class OptionalColumnTransform : RowToRowMapperTransformBase
+    /// <summary>
+    /// This transform is used to mark some of the columns (e.g. Label) optional during training so that the columns are not required during scoring.
+    /// When applied to new data, if any of the optional columns is not present a dummy columns is created having the same properties (e.g. 'name', 'type' etc.) as used during training.
+    /// The columns are filled with default values. The value is
+    ///     - scalar for scalar column
+    ///     - totally sparse vector for vector column. 
+    /// </summary>
+    public sealed class OptionalColumnTransform : RowToRowMapperTransformBase
     {
         public sealed class Arguments : TransformInputBase
         {
@@ -232,6 +239,17 @@ private static VersionInfo GetVersionInfo()
 
         private const string RegistrationName = "OptionalColumn";
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="columns">Columns to transform.</param>
+        public OptionalColumnTransform(IHostEnvironment env, IDataView input, params string[] columns)
+            : this(env, new Arguments() { Column = columns }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to SignatureDataTransform.
         /// </summary>

src/Microsoft.ML.Transforms/RffTransform.cs

@@ -27,20 +27,26 @@ namespace Microsoft.ML.Runtime.Data
 
     public sealed class RffTransform : OneToOneTransformBase
     {
+        private static class Defaults
+        {
+            public const int NewDim = 1000;
+            public const bool UseSin = false;
+        }
+
         public sealed class Arguments
         {
             [Argument(ArgumentType.Multiple | ArgumentType.Required, HelpText = "New column definition(s) (optional form: name:src)", ShortName = "col", SortOrder = 1)]
             public Column[] Column;
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "The number of random Fourier features to create", ShortName = "dim")]
-            public int NewDim = 1000;
+            public int NewDim = Defaults.NewDim;
 
             [Argument(ArgumentType.Multiple, HelpText = "which kernel to use?", ShortName = "kernel")]
             public SubComponent<IFourierDistributionSampler, SignatureFourierDistributionSampler> MatrixGenerator =
                 new SubComponent<IFourierDistributionSampler, SignatureFourierDistributionSampler>(GaussianFourierSampler.LoadName);
 
             [Argument(ArgumentType.AtMostOnce, HelpText = "create two features for every random Fourier frequency? (one for cos and one for sin)")]
-            public bool UseSin = false;
+            public bool UseSin = Defaults.UseSin;
 
             [Argument(ArgumentType.LastOccurenceWins,
                 HelpText = "The seed of the random number generator for generating the new features (if unspecified, " +
@@ -232,6 +238,23 @@ private static string TestColumnType(ColumnType type)
             return "Expected R4 or vector of R4 with known size";
         }
 
+        /// <summary>
+        /// Convenience constructor for public facing API.
+        /// </summary>
+        /// <param name="env">Host Environment.</param>
+        /// <param name="input">Input <see cref="IDataView"/>. This is the output from previous transform or loader.</param>
+        /// <param name="newDim">The number of random Fourier features to create.</param>
+        /// <param name="name">Name of the output column.</param>
+        /// <param name="source">Name of the column to be transformed. If this is null '<paramref name="name"/>' will be used.</param>
+        public RffTransform(IHostEnvironment env,
+            IDataView input,
+            int newDim,
+            string name,
+            string source = null)
+            : this(env, new Arguments() { Column = new[] { new Column() { Source = source ?? name, Name = name } }, NewDim = newDim }, input)
+        {
+        }
+
         /// <summary>
         /// Public constructor corresponding to <see cref="SignatureDataTransform"/>.
         /// </summary>